Hemodialysis is well-known and often the prescribed therapy modality for kidney failure, as opposed to kidney transplantation, but has the disadvantage of requiring removing blood from the patient's vasculature, treating the blood ex-vivo by dialysis and/or ultrafiltration to remove the toxins and then return the blood to the patient's body. The substantial disadvantages of hemodialysis, both to the patient and the care giver, include frequent vascular access, coagulation in extracorporeal circuits, susceptibility to infections, hemolyses, "peaks and valleys syndrome", heavy high tech apparatus, patient immobility and extensive required medical supervision and care, as well as the extremely high costs. Although recent advances in acute hemodialysis using renal replacement therapy techniques in which continuous ex-vivo ultrafiltration is emphasized show improvements, the removal of whole blood still has grave disadvantages.
In U.S. Pat. Nos. 4,950,224, 5,152,743 and 5,151,082 there are disclosed methods and apparatus for carrying out in vivo plasmapheresis for separating plasma from other blood components within the body and blood vessels of the patient. The apparatus uses pumping means to motivate the flow of fluid from within the in vitro system, whereby blood plasma is pumped from the patient to a treatment means, such as a dialyzer apparatus in which toxic metabolic waste in the plasma is removed. After the dialysate is treated for removal of the waste products and toxins, the regenerated dialysate, i.e., the treated plasma, is returned and reintroduced to the patient's blood stream. Such methods are referred to as plasma dialysis. The methods and apparatus described in the aforesaid patents are incorporated herein by reference.
As advantageous as plasma dialysis methods are, the treatment and apparatus used are unavailable and/or impractical for patients in third world countries or in less privileged environments which do not have extensive medical support infrastructure for purchasing, using, maintaining or managing such systems and methods of use.